ALMOST AS soon as the water stopped pouring on the smoking ruins of Wolf Trap's Filene Center three weeks ago, it was replaced by a new stream: money or (more often) promises of money. Among those joining this rally was the Washington arts community, including some groups with financial problems of their own. Now, that the Wolf Trap bandwagon is rolling at high speed, second thoughts are beginning to be heard: What will be the cost? Who should pay it? How long will it take? And most agonizing of all: Will the money flowing into Wolf Trap be drained from other worthy causes?

Some performing arts groups in Washington are looking with undisguised dismay at the success of current fund-raising efforts for the rebuilding of the Filene Center, which could cost $17.5 million. Peter Jablow, executive director of the Cultural Alliance, said the fund-raising "is bound to drain off the number of contributed dollars for the private sector--not just arts but welfare, social services and across the board." Martin Feinstein of the Washington Opera said that "There's no question it's going to hurt. There is a limited amount of money."

"We're all in need," said James Morris, director of performing arts at the Smithsonian. "Our programs are not secure for next year and the years following. We are actively trying to raise funds. Wolf Trap is a beacon that attracts a lot of attention . . . It's the kind of attention other arts organizations don't command because we don't have a similar visible tragedy to refer to . . . It's unfortunate that there has to be any competition for private support at this difficult juncture."

At least two organizations have already seen these fears translated into fact: "As early as last week in New York," said Doug Trout, director of development for the National Symphony Orchestra, "I discovered that some of our sources are getting direct or indirect solicitations for Wolf Trap, and it will have an effect on our receipts. But I believe that there are sufficient funds in our country to support good causes. If one source dries up, it is our responsibility to discover a new source."

Lee Pasarew, managing director of the Studio Theatre, has a small financial crisis compared to Wolf Trap's--only $6,000--but that's a big crisis for a small company. The Studio, which operates out of a converted factory just off 14th Street, has to make minor repairs on its building to get a permit from the fire marshal before mounting its next production, Brendan Behan's "The Hostage," scheduled for mid-May. "We called around" to past and prospective donors, said Pasarew, "and at least three of them told us that they sympathize but have just given money to Wolf Trap or are about to give money to Wolf Trap and can't help us right now."

"We certainly hope that this support won't hurt other arts groups," says Larisa Wanserski, director of public relations at Wolf Trap. "That's the last thing in the world we want to happen." But she adds that "we need to survive, too. We're trying to rebuild and we're still scrounging for ongoing support like everyone else. It's a special thing. I don't see it as dipping into the one big coffer for funding."

IS THERE A Wolf Trap backlash? Yes, but it's not directed at that venerated institution, one of the city's most popular cultural gathering spots. The federal government (specifically the Park Service) owns Wolf Trap, and Washington arts people feel that the federal government should play a major role in financing reconstruction. "The federal government has a responsibility and should assume that responsibility now," said Jablow. "Instead, they are waiting to see what the private sector is willing to do."

"My feeling," said Harry Bagdasian of the New Playwrights' Theatre, "is that if the government doesn't insure its buildings, it should rebuild them. If New Playwrights' burned down and it wasn't insured, we'd have to replace it."

And from Alton Miller of the Washington Ballet: "A lot of people are saying, 'If the post office burned down, the government would pitch in to rebuild the post office.' "

Some people in government seem to agree with them, at least to some extent. Rep. Frank Wolf (R-Va.), whose district includes the park, has begun preliminary work on legislation. President Reagan personally told Catherine Filene Shouse, who founded Wolf Trap and gave it to the government, that he wanted to see the building restored and the program continued. He appointed Frank Hodsoll, chairman of the National Endowment for the Arts, and Secretary of the Interior James Watt as a two-man task force to help Wolf Trap recover. But action on the legislative or executive front is not likely to come quickly.

At this point, spokesmen for the Park Service really don't know what to say about the future of Wolf Trap. George Berklacy, chief of public affairs, says that the service hopes to help salvage this summer's season and rebuild the facility, but "we don't really have an action plan for that as yet--we haven't had a chance to estimate the damages." Congressional action will be needed to procure any money needed for rebuilding. The government's "self-insurance" program, in practical terms, means simply that the government is willing to take the risk of not insuring its property. There is no special fund for rebuilding government property destroyed by fire.

Wolf Trap has a history of disastrous fires dating back to its origin, but no history at all of government-financed reconstruction. The Filene Center was 60 percent destroyed by fire in March 1971, before its opening, and the reconstruction was financed by private contributions. In the autumn of 1976, the Children's Theater in the Woods was destroyed by fire and replaced with private funds. In 1979, the Composer's Cabin burned down. It has not yet been replaced.

"I have said that I feel that in giving Wolf Trap its buildings I gave a challenge to my government and to people everywhere," wrote Kay Shouse after the fire. While people everywhere may be responding to the latest challenge, the government, so far, is not.

INVENTIVENESS and optimism have been, of necessity, in abundance in the world of the arts. And today, there are those who find a beacon of hope in the ashes of Wolf Trap. This school of philosophy was perhaps summed up best by the Washington Ballet's Miller: "All I can say is, if someone hands you a lemon, you make lemonade."

Peter Marzio of the Corcoran Gallery compares the competitive fund-raising situation to those streetcorners where there are four gas stations, all doing well because their collective presence has established this location as a place to go for gasoline. "I don't think a fund-raising campaign by one organization hurts another," says Marzio. "The tendency is to think that if someone else takes a dollar away from patron A, that means one dollar less for you, but I don't think it works that way. One kind of giving seems to generate other kinds of giving."

Bagdasian is beginning to lean toward an optimistic view--partly, perhaps, because his company has been offered a $15,000 grant by the Cafritz Foundation: the last $15,000 of its $86,000 fund drive, to be turned over after the other $71,000 is raised. "Some friends are telling me we are not in competition with Wolf Trap, not going after the same dollars," he said, "and I am beginning to hope that it is true."

"If someone offered me $200 right now for the Washington Performing Arts Society," said that organization's Patrick Hayes, "I would tell him to give it to Wolf Trap instead . . . This effort should get people in the habit of giving contributions, and that habit can be helpful to all of us."

Elaine Walter, dean of the School of Music at Catholic University, has made one of the most dramatic gestures of all. As executive director of the Summer Opera Theatre, she has offered Wolf Trap the total proceeds of a gala opening night which she expects to amount to about 40 percent of the company's annual budget. "We will have to do additional fund-raising," she says, "and we all knew already that it was going to be mighty hard to raise money this year."

She believes there is competition for a limited number of dollars and that the weaker groups may "bite the dust." But she sees Wolf Trap as one of the institutions that must survive. "Wolf Trap has been a major factor in promoting rapid cultural growth in Washington, both in quality and in variety," she said. "It has helped to create a climate where many arts organizations could thrive."

One curious but interesting development still has not been adequately interpreted. It relates to one of Martin Feinstein's worries: "We are going to have a radiothon on WGMS next month, so soon after they raised all that money for Wolf Trap. How will the money given to Wolf Trap affect the money available for the Washington Opera?"

There can be no answer to Feinstein's question until the returns are in from the next WGMS fund-raiser, but one partial parallel is already history. Less than a week after WGMS raised more than $135,000 for Wolf Trap through an on-the-air campaign, another good-music station, listener-supported WETA-FM, ran its regularly scheduled spring marathon. It raised more than $185,000, setting a new record. In effect, between the two campaigns, nearly $150,000 of unexpected resources had turned up through solicitation by radio. Will the Washington Opera find still more when it goes back on the airwaves next month? Stay tuned.